University of Vermont
Department of Plant and Soil Science

Summer
News Article

PLANTING A BUTTERFLY GARDEN

Dr. Leonard Perry, Horticulture Professor
University of Vermont

Butterflies are important pollinators of our food and flower crops. To
keep them coming, or if you just enjoy their beauty, provide them with the
habitat they need. Butterflies are attracted to landscapes that
provide warmth, water, food, and shelter—preferably all near each other.

The first step in creating a butterfly garden is to choose the proper site
for them, and preferably one where you can observe them. Butterflies are
most active in warmth and bright sunlight, so pick a spot that gets plenty
of sun. The air temperature must be at least 40 to 60 degrees (F) for
them to become active. Place perches for their sunning in, or near,
the garden where butterflies can land and spread their wings. These
include flat stones, wooden fence posts, and areas of mulch.

Water for butterflies should be provided in the form of a puddle, not
birdbaths, ponds, or large water features. Containers could be a small
trench in the soil lined with plastic, a plastic pail buried in the ground,
or a dish. Fill the container with sand. Place a few rocks and
twigs on the sand to provide landing sites within reach of the water.
Then fill the container with water to the level of the sand.

Provide the least hostile environments to butterflies—those least attractive
to birds and other predators. One way to keep birds away is with the
use of inflatable snakes. Or you can place birdbaths and feeders a distance
from the garden. Sticky tape and flytraps will help catch preying
insects, as you want to avoid the use of insecticides.

The same products that kill undesirable insects, including electric bug
zappers, also kill butterflies and moths. At some stage of their life
cycle, all butterflies are susceptible to chemicals, even some of the least
toxic ones such as biological Bt products. Some of the feeding damage
you’ll see on leaves is probably caused by caterpillars, which you need to
tolerate in order to later have butterflies! Usually such feeding is
minor, and doesn't pose a significant nor long term threat to your plants.

A wide variety of plants attract butterflies. Remember that you’ll need to
provide food for the larvae, as well as the adult butterflies (mainly flower
nectar). Most species are fussy about where they lay their eggs,
selecting plants from specific families that will provide appropriate food
for hatching caterpillars. Monarch caterpillars only eat milkweeds.
Black swallowtail larvae eat leaves of dill, parsley, carrot, and
fennel. Painted lady caterpillars eat thistle leaves. In
general, caterpillars like weeds such as clover, thistle, and milkweed. If
possible, leave a few weeds for them along the edge of the garden or in
nearby areas.

Add some vegetables and herbs to encourage butterflies to lay eggs in the
garden. Caterpillar forage plants include parsley and ornamental
cabbage, which are excellent edging plants for the flower garden.
Clover makes a good "living mulch path". Carrot and dill add
fine-textured, attractive foliage to the flower garden.

In general, adult butterflies are attracted to red, orange, yellow, purple,
and pink flowers. Also they prefer flowers that are in clusters or
flat-topped groupings, and which have short flower tubes. Since they
have evolved with flowering native plants, it is important to include these
in your landscape. A good listing of native plants, by region or state, can
be found from the Lady Bird Johnson Wildflower Center (www.wildflower.org/collections/).

To encourage butterflies to stay all summer long, select plants that flower
at different times of the season to provide a continual supply of nectar.
Since butterflies are near-sighted, plant more than one of a
particular flower to attract them. Butterflies rely on smell more than
sight in locating nectar plants, so scent increases the chance of a flower
being visited by them. (Their sense of smell is located in their
clubbed antennae.)

Planting nectar sources in sites protected from wind helps butterflies
fly and forage in the garden with less effort. You could plant
windbreaks of trees and shrubs that would provide cover and perhaps even
food. Houses, garages, wood fences, and stone walls also serve as
windbreaks.

Some butterfly species prefer, even require, overripe fruit to feed
upon. Plant some shrubs and trees that produce fruit, such as
shadbush, crabapples, blackberries, raspberries, blueberries, and
viburnum. Just keep in mind that too many such fruit on the ground
also may attract bees, hornets, and wasps.

Since species may overwinter in any of their four stages— egg, larva or
caterpillar, chrysalis or pupa (which is the stage that metamorphoses), and
the adult butterfly-- a variety of winter cover is needed.
Butterflies overwintering in the adult stage may use the peeling bark on
trees, perennial plants, and old logs or fences. Old sheds, barns, or
houses also provide overwintering sites. Similar sites are used by
overwintering pupae. Butterfly hibernation boxes are seldom used by
them, but more frequently by wasp colonies.

Butterflies overwintering as caterpillars or eggs use herbaceous perennials,
shrubs, and trees. Leave the leaf litter and dead plant parts of
perennials in the garden until spring to provide cover for them from
predators such as birds.

You can learn more about butterfly gardens, and how to officially certify
yours, from the North American Butterfly Association (nababutterfly.com/).